This invention relates to a strip accumulator for use in a continuous processing line. More particularly, this invention relates to a strip accumulator which holds inner and outer convolutions of strip material, the convolutions being defined by inner and outer roll baskets.
Industrial processing lines which utilize a strip material, such as a metallic strip material, as an input usually require that the strip be continually fed thereto. The input strip is usually fed from a supply coil to the processing line and because it would be highly undesirable to stop the processing line upon depletion of a coil, strip accumulators, such as that shown in U.S. Pat. No. 3,506,210, are placed between the supply coil and the processing line. These accumulators receive strip from the supply coil, hold or store a quantity of the same and at the same time pay out strip so held to the processing line. Such accumulators are thus intended to permit the processing line to remain active, utilizing strip stored in the accumulator, during the time a new supply coil is attached, as by welding, to the end of a coil which has just been depleted.
In these prior art accumulators, such as U.S. Pat. No. 3,506,210, inner and outer convolutions of strip material are defined by inner and outer sets of rollers. These rollers are oriented generally in a circular configuration and as the strip builds up against them, they are designed to move radially to maintain proper spacing between the convolutions.
The manner in which the prior art has accomplished this radial expansion has not been totally satisfactory, particularly economically, since the design is quite complex, having a number of parts with attendant maintenance problems. In the prior art the shafts of the inner set of rollers are supported on one end by a linkage arrangement and extend through guide slots in a heavy backing plate. Through a linkage arrangement for each roller, rotation of a disk by a pneumatic cylinder moves the rollers radially. Such an arrangement not only includes hundreds of moving parts and heavy support structure, but it also is subject to severe bending stresses because of the cantilever construction.
In some prior art designs the outer set of rollers are mounted much like the inner set construction just described, that is, movable in a track formed in the backing plate with attendant linkages and the like. In the design of U.S. Pat. No. 3,506,210, the outer set of rollers are cantileverly extended from arms which are affixed to rotatable sleeves. The sleeves include a sprocket so that a chain actuated by a pneumatic cylinder will rotate all the sleeves to move the rollers. This design suffers from the same problems including the multiplicity of parts and cantilever construction, as discussed previously.
Another problem in prior art accumulators is their requirement to have a separate guide system for the sides of the strip, again calling for a number of complex parts. Usually the strip in both the inner and outer convolutions is maintained laterally positioned by two sets of rollers, each set contacting one edge of the strip. These edge guides are usually journalled in brackets extending from the backing plate with the brackets being slotted so that the position of the rollers may be adjusted to accommodate strip of varying widths.
In short as to the prior art accumulators, the guiding and accumulating functions are accomplished by a complex design requiring a number of moving parts all supported, in one way or another, by a heavy backing plate which itself must be precision machined to include a plurality of tracks or guide slots. As such, these accumulators are expensive to manufacture and maintain, thereby rendering them economically feasible at best only for large installations.